Thousands march to the Arizona Capitol for higher teacher pay and school funding on the first day of a state-wide teacher strike Thursday, April 26, 2018, in Phoenix.

Teachers are making less today than they did more than 20 years ago and their wages have fallen relative to comparable workers, according to a new research paper by the labor-friendly Economic Policy Institute.

When adjusting for inflation, teacher pay has decreased by $27 a week since 1996, falling from $1,164 weekly to $1,137 in 2017. Meanwhile, the study found, other college graduates' average weekly wages have increased from $1,339 to $1,476 over the same time period.

The paper, authored by EPI Distinguished Fellow Lawrence Mishel and UC Berkeley Economist and EPI Research Associate Sylvia Allegretto, comes as teachers across Texas and the country have pushed elected officials for higher wages and more spending on public education.

Mass teacher protests over state's education spending caused school closings in West Virginia, Oklahoma and Kentucky. In Texas, school district officials and teacher union leaders have pushed the state to update its antiquated school funding formulas and increase the share it pays towardeducational expenditures.

"Deteriorating teacher pay is not just a fairness issue. Eliminating the teacher pay penalty is crucial to building the teacher workforce we need. In order to recruit and retain talented teachers, school districts need to address the inadequacy of teacher pay," Mishel said. "As we've seen across the country in states like Washington, Arizona, and Oklahoma, teachers are tired of working demanding jobs with low pay."

While the EPI study noted teachers usually enjoy better benefits packages than similar workers, those extras do little to change the existing wage gap. With benefits included, teachers are left with a 11.1 percent compensation gap when compared to other college graduates.

The study noted that the relatively low wages may have contributed to teacher shortages across the country. Increased emphasis on testing, state budget cuts and growing class sizes also have made it difficult for schools to retain mid- and senior-level teachers.

"To address teacher shortages, it is necessary to focus on both recruiting and retaining high-quality teachers," said Allegretto, "Many policies are needed to accomplish this goal, and providing appropriate compensation is a necessary, major tool in addressing shortages."

The wage penalty has grown remarkably among women. In 1960, female teachers earned 14.7 percent more than comparable female workers. However, in 2017, the authors find a 15.6 percent wage gap for female teachers.

The male teacher wage gap was 22.1 percent in 1979 and improved to 15.1 percent in the mid-1990s, but worsened in the late 1990s and early 2000s. It stood at 26.8 percent in 2017.

The erosion of teacher pay relative to that of comparable workers since 2008 reflects state policy decisions rather than the result of revenue challenges brought on by the Great Recession. A recent study found that most of the 25 states that still were spending less for K-12 education in 2016 than before the recession also had enacted tax cuts between 2008 and 2016. In fact, eight of the 10 states with the largest reductions in education funding since 2008 were states that had reduced their overall "tax effort"— meaning through tax cuts or other measures they were collecting less in taxes relative to their capacity to generate tax revenue. These eight states were Alabama, Arizona, Florida, Georgia, Idaho, Kansas, Oklahoma, and Virginia.

Researchers used the measure of weekly wages in an effort to adjust for the two months during which teachers are not in the classroom for summer break. Allegretto and Mishel also used data on teacher and professionals benefits and wages to adjust the teacher wage estimates for things such as better benefit packages.